1. Field of the Invention
The present invention relates to a tool, and more particularly to a quick assembly pneumatic tool that is convenient for assembly and maintenance.
2. Description of Related Art
Pneumatic or air-driven impact wrenches are extensively used to rapidly fasten or loosen bolts or nuts. A conventional pneumatic impact wrench has a housing, a rear cover, an air cylinder and an impact assembly.
The housing is formed as one piece and has a handle and a barrel. The handle has an air inlet and a trigger assembly. The air inlet is selectively connected to an air supply providing compressed air to the housing through the air inlet. The trigger assembly selectively opens or closes the inlet. The barrel is formed on and communicates with the handle and has a front end, a rear end and a chamber.
The rear cover is mounted on the rear end of the barrel to seal the chamber.
The air cylinder is mounted in the chamber and has a cylinder casing and a rotor. The cylinder casing is mounted securely in the chamber and has multiple air through holes defined therethrough to allow compressed air to enter the cylinder casing. The rotor is mounted rotatably in the cylinder casing and is driven to rotate by the compressed air.
The impact assembly is mounted in the chamber of the housing adjacent to the front end, is connected to the rotor and has a transmission member, an anvil and multiple hammers. The transmission member is connected to and selectively driven to rotate by the rotor. The anvil, also called a transmission shaft, is mounted longitudinally through the transmission member, protrudes out of the front end of the barrel and may be connected detachably to a tool bit such as screwdriver. The hammers are mounted pivotally on the transmission member and impact the anvil when the transmission member is rotated so that the impacted anvil acquires torque to substantially rotate synchronously with the rotor and the transmission member.
Because the housing is formed as one piece, the impact assembly and air cylinder need to be inserted into the chamber in turn through the rear end of the barrel. Such assembling frequently results in misalignment between the impact assembly and the air cylinder.
To overcome the shortcomings, the present invention provides a quick assembly pneumatic tool to mitigate or obviate the aforementioned problems.